1. Field of the Invention
The present invention relates to a signal-processing method, a signal-processing system, and a semiconductor device configured to detect the physical-quantity distribution (hereinafter often referred to as a physical-information-acquisition device). More specifically, the present invention relates to a signal-processing technology adapted to acquire information used for a predetermined object by reading a signal. The signal-processing technology is useful for a semiconductor device configured to detect the physical-amount distribution. The semiconductor device includes, for example, a solid-state image-pickup device that includes at least two unit components arranged in a predetermined manner. Each of the unit components has sensitivity to an externally-transmitted electromagnetic wave including light, an X-ray, and so forth. The solid-state image-pickup device can read the physical-quantity amount converted into an electric signal by each of the unit components. The signal-processing technology includes zoom processing, defective-pixel-correction processing, vertical-line-noise-correction processing, dynamic-range-enlargement processing, and so forth.
2. Description of the Related Art
Physical-amount-distribution-detection semiconductor device including at least two unit components (e.g., pixels) have been used in various fields. The unit components are arranged in a line or a matrix and each of the unit components has sensitivity to a change in the physical amount including an externally transmitted electromagnetic wave such as light, an X-ray, and so forth, and/or a pressure (contact or the like).
For example, in the field of video apparatuses, solid-state image-pickup devices including an image-pickup element (an image-pickup device) of the charge-coupled-device (CCD) type, the metal-oxide-semiconductor (MOS) type, or the complementary-metal-oxide-semiconductor (CMOS) type have been used, where the image-pickup element detects a change in light (an example electromagnetic wave), which is an example physical quantity. Here, the term “solid-state” denotes a semiconductor. An example of the above-described solid-state image-pickup element is disclosed in “Kazuya Yonemoto “Foundation and Application of CCD/CMOS Image Sensor”, CQ Publishing, 2003, Aug. 10, first edition”.
For example, since the solid-state image-pickup elements such as a CCD image sensor or a COM image sensor are increasingly downsized and low priced, various types of video apparatuses using the solid-state image-pickup element, such as a digital still camera configured to photograph a still image, a mobile phone with a camera, a video camera configured to photograph a moving image, and so forth have become widely available. Particularly, since the power consumption and cost used for manufacturing the CMOS image sensor are lower than those of the CCD image sensor, the CMOS image sensors receive attention, as image sensors that will replace the CCD image sensors in future.
As the semiconductor technology progresses in recent years, the number of pixels used in the solid-state image-pickup element is rapidly increased. For example, solid-state-image-pickup elements with several million pixels have been developed and used for digital still cameras and movie-video cameras, so as to achieve high resolution therein. Particularly, the CMOS image sensor is a solid-state image-pickup device having a photoelectric-conversion element and a read circuit in each of the pixels. Since the pixels can be randomly accessed and data can be read therefrom with high speed, the CMOS sensors receive much attention, as promising sensors.
Further, in the field of computer apparatuses, fingerprint-identification devices configured to detect the fingerprint-image information based on a change in the electrical characteristic and/or the optical characteristic on the basis of a pressure. The fingerprint-identification devices read the physical-quantity amount converted into an electrical signal by the unit components (corresponding to pixels in the solid-state image-pickup device).
The above-described solid-state image-pickup devices include amplification solid-state image-pickup devices including a pixel-signal-generation unit configured to generate a pixel signal responsive to a signal electrical charge generated by an electrical-charge-generation unit. The pixel-signal-generation unit includes at least one pixel that is formed, as an amplification solid-state image-pickup element (referred to as an active pixel sensor (APS) or a gain cell) having an amplification-drive transistor such as a static-induction transistor, a MOS transistor, and so forth. For example, many of the CMOS solid-state image-pickup devices have the above-described configuration.
Where the pixel signal is read from the amplification solid-state image-pickup device, address control is performed for a pixel unit including the arranged unit components so that the pixel signals transmitted from the unit pixels are arbitrarily selected and read. Namely, the amplification solid-state image-pickup device is provided, as an address-control solid-state image-pickup device.
For example, where the amplification solid-state image-pickup element is formed, as an X-Y-address solid-state image-pickup element including unit pixels arranged in a matrix, each of the unit pixels is formed, as a MOS active element (a MOS transistor), so that each of the unit pixels has the amplification function. Namely, a signal electrical charge (a photoelectron) accumulated in a photodiode functioning as the photoelectric-conversion element is amplified by the active element and read, as image information.
In the above-described X-Y-address solid-state image-pickup element includes, for example, a pixel unit having many pixel transistors arranged in a two-dimensional matrix. In the pixel unit, accumulation of the signal electrical charges corresponding to incident light is started for every line (row) or pixel and the current or voltage signals corresponding to the accumulated signal electrical charges are read in a predetermined order from the pixels according to address specification.
Here, in the MOS (including CMOS) transistor, the pixel transistors corresponding to a single line are accessed at one time and pixel signals are read from the pixel unit in lines. In many cases, the pixel signals corresponding to the single line are read and transmitted to the output side in sequence. For example, the signals of the pixels arranged in a matrix are transmitted to a vertical-signal line in lines and further transmitted from the vertical-signal line in a horizontal direction to a horizontal-read line in sequence.
FIG. 11 shows an example configuration of an image-pickup device 801 using an ordinary CCD image-pickup element. FIG. 12 is a timing chart showing example operation timing of the image-pickup device 801. An image-pickup device 801 forms a camera system by using the CCD image-pickup element. The image-pickup device 801 includes a CCD solid-state image-pickup element 802 that has an image-pickup unit (an image-element unit) 810 including many photodetection sensors such as photodiodes, as a main unit, an analog-signal-processing unit 820 configured to perform desired signal processing for an analog image-pickup signal transmitted from the solid-state image-pickup element 802, and a signal-conversion unit 824 configured to convert the analog image-pickup signal that is processed and transmitted from the analog-signal-processing unit 820 into digital image-pickup data.
Further, the image-pickup device 801 is formed, as a large-scale-integrated circuit (LSI) configured to perform signal processing. The signal-processing LSI includes a digital-signal processor (DSP) or the like. The image-pickup device 801 includes a post-stage-signal processing unit 826 configured to perform desired signal processing for the digital-image-pickup data transmitted from the signal-conversion unit 824 and a control unit 840 configured to control the solid-state image-pickup element 802 and the post-stage signal-processing unit 826. The control unit 840 is formed, as a CCD-control LSI such as a CCD driver. The post-stage-signal processing unit 826 and the control unit 840 are configured to control each other.
The solid-state image-pickup element 802 includes a sensor-circuit unit 813 configured to drive the image-pickup unit 810 and an amplification-and-drive unit 819 configured to amplify and externally transmit an analog pixel signal transmitted from the solid-state image-pickup element 802.
In the above-described image-pickup device 801, an image-pickup signal transmitted from the CCD solid-state image-pickup element 802 is an analog signal. As shown in FIG. 12, timing-control signals generated by the post-stage-signal-processing unit 826 and/or the control unit 840 are transmitted and/or received in frames. An analog-signal transmitted from the solid-state image-pickup element 802 is A/D-converted by the signal-conversion unit 824 and image-pickup data is transmitted line by line to the post-stage-signal processing unit 826 in a parallel (see FIG. 12) or serial manner in a data-output period in a single horizontal period.
The post-stage-signal-processing unit 826 receives the image-pickup data line by line in a horizontal-blanking period, for example, and performs desired signal processing line by line, so as to generate the image corresponding to a single frame. Further, the solid-state image-pickup element 802 does not transmit a control signal or the like in the horizontal-blanking period.
FIG. 13 shows an example configuration of an image-pickup device 851 using an ordinary CMOS image-pickup element. The operation timing of the image-pickup device 851 is the same as that shown in the timing chart of FIG. 12.
Where the CMOS image-pickup element is used, peripheral circuits including a driver function, a signal-amplification unit, an A/D-conversion unit, and so forth can be formed by the same process as that of an image-pickup unit 860. Therefore, the peripheral circuits and the image-pickup unit 860 are formed on one and the same semiconductor substrate. Namely, the peripheral circuits are included in a sensor. The above-described configuration is referred to as a system-on-chip configuration (refer to Chapter 7 of “Foundation and Application of CCD/CMOS image sensor” ). FIG. 13 shows the above-described system-on-chip configuration.
Te image-pickup device 851 using the CMOS image-pickup element includes, for example, the image-pickup unit (a pixel-element unit) 860 including many photodetection sensors such as photodiodes, a sensor-circuit unit 863 configured to drive the image-pickup unit 860, an analog-signal-processing unit 870 configured to perform desired signal processing for an analog image-pickup signal transmitted from the image-pickup unit 860, and a signal-conversion unit 874 configured to convert the analog image-pickup signal that is processed and transmitted from the analog-signal-processing unit 870 into digital image-pickup data. The above-described units 860, 863, 870, and 874 are provided on one and the same semiconductor substrate.
Further, the image-pickup device 851 is a signal-processing LSI including the DSP or the like. The image-pickup device 851 includes a control-and-signal-processing unit 880 having a post-stage signal-processing unit configured to perform desired signal processing for the digital image-pickup data transmitted from the signal-conversion unit 874 and a control unit configured to control the sensor-circuit unit 863 and the analog-signal-processing unit 870. The control-and-signal-processing unit 880 and the image-pickup unit 860 are provided on one and the same semiconductor substrate.
Thus, in the image-pickup device 851 including the analog-signal-processing unit 870, the signal-conversion unit 874, the control-and-signal-processing unit 880, and the CMOS image-pickup unit 860 that are provided on one and the same semiconductor substrate, timing-control signals generated by the control-and-signal-processing unit 880 are transmitted and/or received in frames, analog signals transmitted from the analog-signal-processing unit 870 are A/D-converted by the signal-conversion unit 874, and image-pickup data is transmitted line by line to the control-and-signal-processing unit 880 in a data-output period in a single-horizontal period in a parallel manner (see FIG. 12) or a serial manner.
The control-and-signal-processing unit 880 receives the image-pickup data line by line in a horizontal-blanking period, for example, and performs desired signal processing lien by line, so as to generate the image corresponding to a single frame. Further, the signal-conversion unit 874 does not transmit a control signal or the like in the horizontal-blanking period.
Thus, in the camera system using the known image-pickup element performs timing control in frames by using an LSI other than the image-pickup element including the DSP, the CCD driver, and so forth. Although image signals are transmitted from the image-pickup element in lines, the image signals are controlled at predetermined timing in frames and subjected to signal processing in frames.
Further, when performing a function having a higher value added, the image signals are also controlled in frames. For example, where gain adjustment, zoom (image enlargement) processing, and so forth are performed, control signals (e.g., operation-timing signals) are transmitted and received in frames among a plurality of chips including the CCD solid-state image-pickup element 802, the control unit 840 having the CCD driver or the like, the signal-conversion unit 824, the post-stage-processing unit 826, and so forth. Image data divided in frames is subjected to one and the same signal processing line by line.
The difference between the CCD image-pickup device shown in FIG. 11 and the CMOS image-pickup device shown in FIG. 13 is described below. In the CMOS image-pickup device, the analog-signal processing unit 870, the signal-conversion unit 874, and the control-and-signal-processing unit 880 are provided on the same semiconductor substrate as that of the CMOS image-pickup unit 860. Further, the image-pickup device 851 itself functions, as the CMOS solid-state image-pickup element.
Therefore, in the CMOS image-pickup device, the image signals are also controlled in frames, where the function having the higher value added is performed. Further, control signals (e.g., operation-timing signals) are transmitted and received in frames among the control-and-signal-processing unit 880, the analog-signal-processing unit 870, and the signal-conversion unit 874. Image data divided in frames is subjected to the one and the same signal processing line by line.